Drug targeting strategies for photodynamic therapy

Area of Science:

• Biomedical Engineering
• Drug Delivery Systems
• Photodynamic Therapy

Background:

• Therapeutic treatments face limitations due to drug non-selectivity and high effective concentrations, leading to side effects.
• Targeting drugs to specific tissues can improve selectivity, reduce systemic toxicity, and enhance therapeutic efficiency.
• Photodynamic therapy (PDT) utilizes photosensitizers (PS) activated by light to produce cytotoxic species, but systemic PS distribution causes generalized photosensitization.

Purpose of the Study:

• To review strategies for improving the targeting of photosensitizers (PSs) in photodynamic therapy (PDT).
• To discuss methods for enhancing PS selectivity towards diseased tissues, thereby minimizing side effects.
• To emphasize the role of peptides and proteins in targeted PDT approaches.

Main Methods:

• Review of existing literature on drug targeting strategies in human pathologies.
• Analysis of methods to modify photosensitizers (PSs) for enhanced tissue-specific accumulation.
• Exploration of targeting agents including peptides, proteins, non-proteic ligands, and nanoparticles.

Main Results:

• Targeting strategies can exploit differences in receptor expression or enzyme activity between diseased and normal cells.
• Modification of PSs with peptides, proteins, or encapsulation in nanoparticles can improve targeting efficiency.
• Functionalization with organometallic ligands offers potential for targeted and combined therapies.

Conclusions:

• Targeted delivery of photosensitizers (PSs) is crucial for improving the efficacy and patient acceptance of photodynamic therapy (PDT).
• Peptide and protein-mediated targeting, along with nanoparticle encapsulation, represent promising avenues for advanced PDT.
• Further research into targeted therapies can overcome current limitations in treating various human pathologies.